HVACR pipe

ABSTRACT

The present invention relates to a pipe suitable for conveying fluids in HVACR applications, which pipe comprises an inner tube delimiting an inner space or passageway for a fluid, an insulating cover and an anti-corrosion layer.

TECHNICAL FIELD

The present invention relates generally to pipes or tubes for HVACR(Heating, Ventilation, Air-Conditioning, Refrigeration) applications orsystems.

In particular, the present invention relates to pipes or tubescomprising an anti-corrosion layer.

BACKGROUND

Heating, ventilation, air conditioning and refrigeration (HVACR) is thename of a technology which has greatly developed in recent years.

One of the main aims of such technology is to provide thermal comfortand acceptable indoor air quality: to obtain such results the functionsof heating, ventilation, air conditioning and refrigeration are strictlyinterrelated.

HVACR technology finds application in residential structures, incommercial or industrial buildings, hospitals, vehicles, in marineenvironments, etc.

An important part of HVACR technology is constituted by pipes or tubes,which are used to convey fluids and/or gases to accomplish the HVACRpurposes. Such fluids and/or gases can have a hot or cold orintermediate temperature and, in order to provide thermal insulation,the pipes or tubes are generally equipped with an insulating coatinglayer.

Such pipes are for example those referred to by the designation B1003-16 of the ASTM international standard.

However, when the pipes are exposed to the outdoor, pollution, such asfor example heavy metals, fine dust, acid rains, or some corrosiveelements or agents could cause damages. Furthermore, during workingsteps and installation steps, the pipe is subject to damages andcorrosive environments.

Therefore, the need is felt to provide HVACR pipes or tubes with ananti-corrosion layer or coating, in order to avoid damages and similarunwanted events or to protect the pipe from chemicals within theinsulation which can cause corrosion of any kind.

Furthermore, pipes or tubes with an anti-corrosion layer or coating areneeded also when they contain flammable refrigerants, in order to besafer.

SUMMARY OF THE INVENTION

The present invention discloses a pipe or tube, comprising an innertube, especially suitable for being used in HVACR applications. In oneversion, the inner tube is suitable to contain at least one refrigerantfor a HVACR application. On this regard, it includes an inner space orpassageway through which fluids and/or gases and/or air and/orrefrigerants can flow.

With the expression “refrigerants” is here to be intended fluids whichare conveyed in a cooling or refrigeration circuit, and they, owing totheir state change, make it possible to heat or cool other fluids orcomponent of a thermal machine.

As a matter of fact, the inner space or passageway is a channelextending for all the length of the inner tube, with an inlet opening atone end and an outlet opening at the other end of the tube or rather ofthe pipe, so that a fluid inserted in the inlet opening of such innerspace or passageway is conveyed through the latter until reaching therespective outlet end, where the fluid goes into a conditioningequipment, such as a VRF, minisplit, A/C unit, etc.

In one embodiment, the pipe further has at least one insulating layer,and when the pipe is pre-insulated, it is called “line set”.

In some other embodiments, the pipe comprises several coating and/orinsulating layers.

Advantageously, a pipe according to the present invention is suitablefor connecting the external and internal unit of air conditioningmachines. Such pipe can be connected to other pipes or to a component ofsuch machines.

In some embodiments, the cross section of the pipe and/or of the innertube is rounded and/or circular.

Advantageously, the pipe comprises an anti-corrosion layer applied onthe inner tube. Preferably, the anti-corrosion layer is tubular. Stillmore preferably, the anti-corrosion layer is fluid tight and not porous,for example liquid and/or gas tight. In this respect, preferably thesole openings delimited by the tubular anti-corrosion layer are at theends of the latter.

In some embodiments, the pipe comprises an anti-corrosion layer,preferably tubular, sandwiched between the inner tube and at least oneinsulating layer.

In some embodiments, the pipe comprises more layers of anti-corrosionlayer.

In some embodiments, the pipe comprises an insulating cover, which actsas a coating and/or insulating layer.

The insulating cover is placed above the inner tube or above theanti-corrosion layer.

The insulating cover is made of or comprises at least one of thefollowing materials: a foam insulation material, i.e. a materialundergoing an expansion under given conditions (temperature, pressure,etc.) until obtaining the final, for example sheet or tubular, shape.Optionally, the foam insulation material has a closed-cell structure.

The foam insulation material comprises or consists of for example anelastomeric and/or polyethylene foam, polyethylene (PE) or rubber,polyvinyl chloride (PVC), (acrylo)nitrile-butadiene rubber (NBR), amixture of PVC and NBR, ethylene propylene diene monomer (EPDM),polypropylene (PP) based foam, polystyrene, polyisocyanurate, etc., aclosed-cell foam, for example based on at least one polymer, such as forexample PVC/NBR, NBR and EPDM, etc., a fibrous or cellular typematerial, cross-linked polyethylene (PEX), etc.

In some embodiments, the pipe further comprises a protective jacket.Also the protective jacket can act as coating and/or insulating layer.

The protective jacket is the outermost layer of the pipe.

In another embodiment, the protective jacket is not present.

The protective jacket can be made of at least one of the followingmaterials: a thermoplastic elastomer (TPE) and/or TPE mixture, athermoplastic vulcanizate (TPV), a thermoplastic polyurethane (TPU),polyethylene (PE) or plastic and/or elastomeric material, EPDM,UV-resistant EPDM, PVC, NBR, styrene butadiene rubber (SBR),cross-linked polyethylene (PEX), a mixture of at least one thermoplasticelastomer and of ethylene-propylene-diene-monomer (EPDM), or mixtures ofthe above or a mixture of elastomers and polymers.

The insulating cover and/or the protective jacket can have a tubular orsheet shape when it has/they have to be assembled to form the pipe.

The present invention also refers to a method of producing a pipe.

This method comprises the steps of providing an inner tube, providing aninsulating cover, providing an anti-corrosion material and applying theanti-corrosion material to the inner tube, so as to obtain ananti-corrosion layer from the anti-corrosion material.

In some embodiments, the step of applying the anti-corrosion materialcomprises bonding, gluing, spraying, coating, applying, extruding with,heat welding, etc. the anti-corrosion material in order to obtain theanti-corrosion layer. In a preferred embodiment, the anti-corrosionlayer id directly extruded on the inner tube.

In an embodiment, the insulating cover is obtained by extrusion and/orvulcanization and/or polymerization of the insulating material selectedin order to make the insulating cover.

In another embodiment, the insulating cover can be inserted or appliedon or around the inner tube. Therefore, the method further provides astep of inserting the inner tube, coated with the anti-corrosion layer,inside the insulating cover, if desired through a longitudinal slit madein the insulating cover, or a step of applying the insulating coveraround the inner tube, coated with the anti-corrosion layer.

In an embodiment, the method comprises the steps of providing aprotective material suitable to make a protective jacket, extruding theprotective material in order to obtain a protective jacket on and/orover and/or all around the insulating cover.

In some embodiments, the method comprises at least one of the followingsteps:

-   -   knurling the protective jacket,    -   cooling the pipe and/or the insulating cover and/or the        protective jacket and/or the anti-corrosion layer,    -   cutting the pipe and/or the insulating cover and/or the        protective jacket to a predetermined length,    -   winding the pipe in a reel.

Accordingly, it is an object of the present invention to provide a pipe,suitable to be used in HVACR applications, which is resistant tocorrosion.

An advantage of the present invention is to provide a pipe which isresistant to environmental elements such as temperature, humidity,UV-rays, acids, rain, snow, weather conditions, chemicals within theinsulation, etc.

Another purpose of the present invention is to provide a pipe whichprovides good insulation, resistance to hydrolysis (resistance to hotwater and steam), resistance to UV radiation and at the same time also areasonable production price.

Still another purpose of the present invention is to provide a pipewhich exhibits good resistance to bending, even at very lowtemperatures, as well as good resistance to abrasion.

It is an object to the present invention also to provide a method forobtaining a pipe or tube according to the above-mentionedcharacteristics.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-12 show each a specific method step for obtaining a pipeaccording to the present invention;

FIG. 13 is a cross-sectional view of an embodiment of a pipe accordingto the present invention; and

FIG. 14 is a cross-sectional view of another embodiment of a pipeaccording to the present invention.

DETAILED DESCRIPTION

The present invention relates generally to a pipe or tube 10. Such pipe10 is especially suitable to be used in HVACR applications or systems.

The pipe 10 is a composite pipe, which comprises an inner tube 12 and atleast one coating and/or insulating layer.

In one embodiment of the invention, the pipe 10 comprises severalcoating and/or insulating layers.

The inner tube 12 is made of metal, such as copper, aluminum,stainless-steel, etc., composition or combination thereof, or of aplastic material, or of a composite material, such as for example copperand plastic (such as for example PERT, PE, PEX, PA, etc.), aluminum andplastic (such as for example PERT, PE, PEX, PA, etc.) or stainless steeland plastic (such as for example PERT, PE, PEX, PA, etc.).

Moreover, the inner tube 12 has a thickness ranging for example between0.4 mm and 1.5 mm or between 0.6 mm to 1 mm.

In at least one embodiment of the invention, the pipe 10 is suitable forcontaining at least one refrigerant for a HVACR application.

With this regard, the pipe 10, and in particular the inner tube 12,defines an inner space or passageway 14 through which fluids and/orgases and/or air and/or refrigerants can flow.

As a matter of fact, the inner space or passageway 14 is a channelextending for all the length of the inner tube 12, with an inlet openingat one end and an outlet opening at the other end of the tube 12 orrather of the pipe 10, so that a fluid inserted in the inlet opening ofsuch inner space or passageway 14 is conveyed through the latter untilreaching the respective outlet end where it is discharged.

The inner tube 12 is fluid tight and not porous, for example liquidand/or gas tight, since it should prevent the leakage of fluid throughits wall/s. In this respect, the sole openings delimited by the innertube 12 are at the ends of the latter.

In one version of the invention, the cross section of the pipe 10 and/orof the inner tube 12 is rounded and/or circular or oval or regularpolygon-shaped or irregular polygon-shaped. This means that at least theouter cross section of the pipe 10 and/or of the inner tube 12 has thementioned shape, considering that “outer” in the present invention meansthe area opposite the innermost area of the pipe. The innermost area ofthe pipe can correspond to the inner space or passageway 14.

Of course, even the inner cross-section of the inner tube 12 can have aregular polygonal, irregular polygonal or circular or oval cross-sectionor any other suitable cross-section.

The pipe 10 comprises an anti-corrosion layer 16. Advantageously, theanti-corrosion layer 16 protects the inner tube 12 and/or generally thepipe 10 from environmental elements such as temperature, humidity,UV-rays, acids, rain, snow, weather conditions, chemicals inside theinsulation, etc.

According to a version of the invention, the anti-corrosion layer 16 isin contact, preferably continuously or with no discontinuity and for itswhole extension, with the inner tube 12.

According to a version of the invention, the anti-corrosion layer 16 canbe placed in an outer position with respect to the inner space orpassageway 14 of the pipe 10.

The anti-corrosion layer 16 is made of or comprises at least one of thefollowing materials: polyvinyl chloride (PVC) or polyethylene (PE) orpolyamide (PA), polyethylene of raised temperature (PERT), cross-linkedpolyethylene (PEX) based polymers, or mixture thereof. Furthermore, theanti-corrosion layer 16 has a thickness of about 0.05 mm up to 5 mm, forexample between 0.1 mm to 1.5 mm or of about 1 mm or of about 2 mm orbetween 0.1 mm to 1 mm or between 0.2 mm and 0.9 mm, or between 0.2 mmand 0.8 mm or about 0.5 mm, etc. In one version of the invention, theanti-corrosion layer 16 is completely in contact with the inner tube,i.e for example the whole inner surface of the anti-corrosion layer isin contact with the whole outer surface of the inner tube 12.

In another version, for example shown in FIG. 14 , the anti-corrosionlayer 16 is only at least in contact with the inner tube, i.e forexample the inner surface of the anti-corrosion layer 16 is irregular,or wrinkled, or it has ridges and valleys, and therefore it is only inpart in contact with the outer surface of the inner tube 12, which inturn is smooth. Please not that FIG. 14 is not in scale, as its aim isto make visible a possible detail of the present invention.

In this version, it is possible, for the anti-corrosion layer, to betteradapt to the dilatation and/or the shrinkage of the inner tube due totemperature variation from hot to cold.

When the anti-corrosion layer 16 is provided between the insulatingcover 18 and the inner tube 12, the cover 18 has the function ofprotecting the anti-corrosion layer too. The advantage of such kind ofprotection layer is that, when it is inside the pipe 10, i.e. in contactwith the inner tube 12, it is able to protect from corrosion the innertube 12 itself, also during the processing or production steps to whichthe inner tube 12 is subjected to.

Therefore, in one version of the invention, when the insulating cover 18is present, the pipe 10 is a pre-insulated pipe.

Obviously, if the pipe or a respective layer undergoes a corrosion,unwanted losses of gas and/or fluid and/or air and/or refrigerant canoccur, with consequent damages and reduced efficiency for the entireHVACR application.

In this case, a big issue arises in terms of environment, because lossescan be toxic or dangerous or harmful to the environment, in terms ofsafety, as for example new refrigerants are flammable, and also for thelifespan of the tube or the pipe, and pollution and contamination cancause damages to such elements.

Furthermore, as indicated hereinbelow, the inner tube 12 can have or nota protective jacket, and therefore the presence of at least oneanti-corrosion layer ensures a higher resistance for these elements.

In at least one embodiment of the invention, the pipe 10 comprises aninsulating cover 18. The insulating cover 18 is an example of coatingand/or insulating layer of the pipe 10.

The insulating cover 18 can be in contact, preferably continuously orwith no discontinuity and for its whole extension, with theanti-corrosion layer 16. This happens because the anti-corrosion layer16 is placed in contact with the inner tube 12. In such a case, theinsulating cover 18 is in contact with an outer surface of theanti-corrosion layer 16.

The tubular insulating cover 18 covers or encloses the inner tube 12 forthe whole length or longitudinal extension of the latter.

The insulating cover 18 is made of or comprises at least one of thefollowing materials: a foam insulation material, i.e. a materialundergoing an expansion under given conditions (temperature, pressure,etc.) until obtaining the final tubular or sheet shape. Optionally, thefoam insulation material has a closed-cell structure.

The foam insulation material comprises or consists of for example anelastomeric and/or polyethylene foam, polyethylene (PE) or rubber,polyvinyl chloride (PVC), (acrylo)nitrile-butadiene rubber (NBR), amixture of PVC and NBR, ethylene propylene diene monomer (EPDM),polypropylene (PP) based foam, polystyrene, polyisocyanurate, etc., aclosed-cell foam, for example based on at least one polymer, such as forexample PVC/NBR, NBR and EPDM, etc., a fibrous or cellular typematerial, cross-linked polyethylene (PEX), etc.

In the present patent document, the verb “consist” means “include only”,whereas this is not the case of the verb comprise or include.

Furthermore, the insulating cover 18 has a thickness ranging for examplebetween ½ in and 1 in. Preferably, the thickness of the insulating cover18 is constant from one end to the other of the cover 18.

The insulating cover 18 has the function of protecting the inner tube 12and/or the anti-corrosion layer 16.

The inner and outer cross sections of the insulating cover 18 can besuitably shaped, for example one or both of them (inner and outer crosssections) can have a regular polygonal, irregular polygonal or circularor oval or round cross-section. Preferably, the shape and size of innercross-section of the cover substantially corresponds to or rather areslightly higher than the shape and size of the outer cross-section ofthe inner tube 12.

Furthermore, it ensures, in addition to good insulation, resistance tohydrolysis (resistance to hot water and steam), resistance to UVradiation and at the same time also a reasonable production price.

In another embodiment of the present invention, the pipe 10 can comprisealso a protective jacket 20. The protective jacket 20 is an example of acoating and/or insulating layer of the pipe 10.

The protective jacket 20 can be the outermost layer of the pipe 10.

According to another version, the protective jacket 20 can cover theanti-corrosion layer 16, if the insulating cover 18 is not present.

According to another embodiment, in which the anti-corrosion layer 16 isplaced in contact with the inner tube 12, the protective jacket 20 isnot in contact with the anti-corrosion layer 16. In this case it can bein contact, preferably continuously or with no discontinuity and for itswhole extension, with the insulating jacket 18.

Advantageously, no glue is provided between the tubular jacket 20 andthe tubular insulating cover 18, since the same layers are constrainedor connected to one another owing to the obtainment step of the tubularjacket 20 over or around the tubular insulating cover 18 (such as forexample obtained owing to the knurling described below).

The protective jacket 20 can be made of at least one of the followingmaterials: a thermoplastic elastomer (TPE) and/or TPE mixture, athermoplastic vulcanizate (TPV), a thermoplastic polyurethane (TPU),polyethylene (PE) or plastic and/or elastomeric material, EPDM,UV-resistant EPDM, PVC, NBR, styrene butadiene rubber (SBR),cross-linked polyethylene (PEX), a mixture of at least one thermoplasticelastomer and of ethylene-propylene-diene-monomer (EPDM), or mixtures ofthe above or a mixture of elastomers and polymers.

If desired, the material for the obtainment of the protective jacket 20contains at least one suitable additive, such as for example UV orweather retardants, slipping agents, fire or smoke retardants,anti-microbial agents, colors, etc.

Furthermore, the protective jacket 20 has a thickness ranging forexample between 0.2 mm and 2 mm Preferably, the thickness of the jacket20 is constant from one end to the other thereof.

The insulating cover 18 and/or the protective jacket 20 can be providedin tubular or sheet shape, when it has/they have to be assembled to formthe pipe 10.

The protective jacket 20 acts as protective sheath, since it providesresistance to bending, even at very low temperatures, as well as goodresistance to abrasion.

According to one version of the invention, as the inner tube 12 has atubular shape, possible with circular or with another shapecross-section, also the anti-corrosion layer 16, the insulating cover 18and/or the protective jacket 20 can have a tubular shape. In fact, theyare—directly or indirectly—placed or applied on the outer tubularsurface of the inner tube 12 and therefore have the same or comply withthe shape and cross section of the inner tube 12.

The protective jacket 20 can be not porous and fluid tight, although itsmain role is not that of preventing the leakage of fluid through itswalls.

The inner and outer cross sections of the protective jacket 20 can besuitably shaped, for example one or both of them (inner and outer crosssections) can have a regular polygonal, irregular polygonal or circularor oval or round cross-section. Preferably, the shape and size of innercross-section of the jacket 20 substantially corresponds or are slightlyhigher than the shape and size of the outer cross-section of the cover18.

According to an embodiment of the invention, the pipe 10 is a flexiblepipe. Furthermore, as disclosed above, it is a composite pipe, as itcomprises at least one or two coatings applied outwardly with respect toits inner space or passageway 14.

As already indicated, according to an embodiment of the invention, theanti-corrosion layer 16 is applied on the inner tube 12.

This means that the anti-corrosion layer 16 is bonded to, glued with,sprayed on, coated on, applied to, extruded with, heat welded to, etc.the inner tube 12.

In this respect, when glue is used, the glue could be for example aLLDPE or ULDPE based polymers with polar bonding agents.

According to one version of the invention, the application of theanti-corrosion layer 16 occurs without the use of glue or other suitableadhesives.

In addition to the anti-corrosion layer 16, it is possible to listseveral preferred embodiments of pipe according to the presentinvention, which the inventors experimented to provide the bestperformance.

A first preferred embodiment of pipe according to the present inventionhas a tubular insulating cover made of an insulation material comprisingor consisting of a mixture of PVC and NBR, a protective jacket made of amixture of at least one thermoplastic elastomer and of EPDM, and withglue or adhesive between the protective jacket and the insulating cover,so that such tubular layers are constrained or connected or bonded toone another by glue or adhesive.

In accordance with a second preferred embodiment of pipe according tothe present invention, the insulation material of the insulating covercomprises or consists of a mixture of PVC and NBR, the protective jacketis made of at least one thermoplastic elastomer, preferably with no EPDMmixed therewith, and with no glue or adhesive provided between thejacket and the cover, and thus such tubular layers are not constrainedor connected or bonded to one another by glue or adhesive.

In connection instead with a third preferred embodiment of pipeaccording to the present invention, the insulation material comprises orconsists of a mixture of PVC and NBR, the protective jacket is made ofat least one thermoplastic elastomer, preferably with no EPDM mixedtherewith, and glue or adhesive is also provided between the jacket andthe cover, so that such tubular layers are constrained or connected orbonded to one another by glue or adhesive.

A fourth preferred embodiment of pipe according to the present inventionhas instead a tubular insulating cover made of an insulation materialcomprising or consisting of EPDM, a protective jacket made of a mixtureof at least one thermoplastic elastomer and of EPDM, and no glue oradhesive is provided between said tubular jacket and said tubularinsulating cover, and thus such layers are not constrained or connectedor bonded to one another by glue or adhesive.

Referring now to a fifth preferred embodiment of pipe according to thepresent invention, the insulation material comprises or consists ofEPDM, the protective jacket is made of a mixture of at least onethermoplastic elastomer and of EPDM, and glue or adhesive is providedbetween the jacket and the cover, and thus such tubular layers areconstrained or connected or bonded to one another by glue or adhesive.

In accordance with a sixth preferred embodiment of pipe according to thepresent invention, the insulation material comprises or consists ofEPDM, the protective jacket is made of at least one thermoplasticelastomer, preferably with no EPDM mixed therewith, and no glue oradhesive is provided between the jacket and the cover, and thus suchtubular layers are not constrained or connected or bonded to one anotherby glue or adhesive.

With reference then to a seventh preferred embodiment of pipe accordingto the present invention, the insulation material comprises or consistsof EPDM, the protective jacket is made of at least one thermoplasticelastomer, preferably with no EPDM mixed therewith, and glue or adhesiveis provided between the jacket and the cover, and thus such tubularlayers are constrained or connected or bonded to one another by glue oradhesive.

The subject matter of the present invention further relates to a methodof producing or of obtaining a pipe or tube 10.

This method comprises the following steps.

-   -   providing an inner tube 12 (this method step is for example        shown in FIG. 1 ), for example unwinding it from a respective        reel,    -   providing an insulating cover 18 (this method step is for        example shown in FIG. 3 ), for example unwinding it from a        respective reel or obtaining it from a respective container,    -   providing an anti-corrosion material and applying the        anti-corrosion material to the inner tube 12,    -   obtaining an anti-corrosion layer 16 from the anti-corrosion        material.

In order to obtain the anti-corrosion layer, after the application ofthe material, the inner pipe, coated with the anti-corrosion layer, iscooled with water drop (as shown in FIG. 2 ) or spray.

The step of applying the anti-corrosion material comprises bonding,gluing, spraying, coating, applying, extruding with, heat welding, etc.the anti-corrosion material in order to obtain the anti-corrosion layer16. In a preferred embodiment, the anti-corrosion material is extrudedon the inner tube, in order to obtain a strict adhesion of theanti-corrosion material on the inner tube.

The extrusion can be a linear extrusion or a cross-die extrusion, i.e.in a cross direction with respect to the direction of progress of thetube.

The anti-corrosion layer 16 has both the function to protect the innertube 12 and to avoid leakages of fluids from the latter.

The insulating cover 18 can be obtained by extrusion and/orvulcanization and/or polymerization of the insulating material selectedin order to make the insulating cover 18. In another embodiment, theinsulating cover 18 can be inserted or applied on or around the innertube 12. Therefore, the method further provides a step of inserting theinner tube 12, coated with the anti-corrosion layer 16, inside theinsulating cover 18, or a step of applying the insulating cover 18around the inner tube 12, coated with the anti-corrosion layer 16.

Of course, means of guiding the inner tube 12 and the insulating cover18 as well as the other components for obtaining a pipe along the lineare provided in the latter.

This is possible because, for example, the method comprises a step oflongitudinally cutting, for example through a suitable saw 8, such as acircular saw, the insulating cover 18, thereby defining a slit 18 atherein and a step of inserting the inner tube 12 in the slit of theinsulating cover 18.

FIGS. 4 to 6 show such method steps, wherein the inner tube 12 is fed toa coating machine 30 which forces the inner tube 12 along apredetermined pathway, according to which (as shown in FIG. 7 ) theinner tube 12 is drawn close to the insulating cover 18 and guidedthrough the respective longitudinal slit 18 a, so as to enter thelongitudinal opening of the insulating cover 18.

Optionally, enhancing means 34 a, 34 b will enhance the insertion of theinner tube 12 inside the slit 18 a enlarging the slit 18 a. Theenhancing means can include a roller or rotating bearing 34 a and/or awedge 34 b. In particular, the roller or rotating bearing 34 a or wedge34 b of the enhancing means can comprise an end or portion suitable tobe inserted inside the slit 18 a, so that such roller or rotatingbearing or wedge enlarges the slit 18 a, thereby rendering it possiblefor the tube 12 to enter the same 18 a.

Advantageously, the insulating cover 18 guided through the line forobtaining a pipe 10, is bent by bending means, for example includingrollers 35 or the like, at the station of the line where the tube 12 isinserted into the cover 18.

In this respect, owing to the action of the bending means, the cover 18advancing in the line is caused to deviate from a first direction, forexample inclined with respect to the horizontal to a second direction,for example horizontal, inclined with respect to the first direction,for example by an angle ranging among 20° and 80°.

In such case, the tube 12, is drawn along a direction substantiallyparallel to the second direction, at least at the station of the linewhere the tube 12 is inserted into the cover 18, and it (the tube 12) isinserted through the slit 18 a at the point or portion of the line wherethe deviation of the cover 18 occurs.

As it will be understood, the deviation optionally imparted on the cover18, in combination with the guiding direction of the tube 12 with theoptional proviso of enhancing means 34 a, 34 b, determines an easy andrapid insertion of the latter inside the cover 18.

If the insulating cover 18 is to be cut and not directly obtained with aslit, as said a suitable cutter or saw can be provided in the line,preferably upstream of the optional enhancing means 34 a, 34 b and/or ofthe means for deviating the cover 18.

Moreover, the cutter has for example the shape of a rotating or fixedblade able to obtain the through slit 18 a in the cover 18. Obviously,the cutter has a predetermined size, suitable for cutting the wholethickness of the wall of the insulating cover 18.

In this respect, the slit 18 a has a depth corresponding to thethickness of the insulating cover 18, from the outermost surface thereoftill its inner hole or cavity.

As shown in FIG. 8 , after the inner tube 12, coated with theanti-corrosion layer 16, has been inserted inside the insulating cover18, a step of closing the slit 18 a is present. Such closing step can beperformed by welding for example by hot air or UV rays (mainly when PEis used) or gluing (mainly when rubber is used) with a suitable nozzlethe insulating cover 18 at the slit 18 a.

As an alternative, the cover 18 is provided with a slit, and with anadhesive layer suitably covered by a non-adhesive layer arranged at theedges of the cover 18 delimiting the slit; in such case, after the innertube 12 has been inserted into the cover through the slit, thenon-adhesive layer is removed so that the adhesive layers will adhere toeach other closing the slit.

As shown for example in FIG. 9 , according to an embodiment of theinvention, it is possible for the method to comprise the followingsteps, before or after the step of inserting the inner tube inside theinsulating cover or applying the tubular insulating cover around theinner tube:

-   -   providing a protective material suitable to make the protective        jacket 20,    -   extruding the protective material in order to obtain a        protective jacket 20 on and/or over and/or all around the        insulating cover 18. This is accomplished for example by means        of cross hear extruder 36, i.e. an extruder extending in a        direction orthogonal to the advancement direction of the pipe in        the line, or with another suitable machine of the line.

Otherwise, the protective jacket can be provided in tubular shape andthen coupled with the tubular insulating cover 18.

Optionally, a layer of glue is supplied among the insulating cover 18and the protective jacket 20. This step can be carried out with aco-extruder suitable for extruding both the glue and the protectivejacket.

In this respect, a suitable extruder for the protective jacket 20 and,optionally for the glue can be used, for example a die extruder withcross head or another suitable extruder.

As an alternative, the protective jacket 20 can be obtained with a sheetshape and the same is coupled (with glue or not) with or abutted to asheet of insulating cover 18, and subsequently such coupled layers 18,20 are folded so as to obtain a tubular insulating cover with an outertubular protective jacket, and the free ends of the tubular cover+jacketare fixed to one another by means of glue or welding. Thus, in suchcase, the protective jacket 20 would not be applied or obtained on oraround a tubular cover, but such components, cover 18 and jacket 20,would be rendered tubular starting from a sheet together andsimultaneously.

After that, as shown in FIG. 10 , the method can comprise a step ofknurling the protective jacket 20. This is made by a shaping machine 38,which comprises for example suitable tools for impressing or shaping theouter surface of the protective jacket 20.

In this way, the outer surface of the protective jacket 20 has a knurledor waved or rough pattern or corrugations or with other patterns orcorrugations, such as a longitudinal pattern or corrugations 20 a orwith an annular rings pattern or corrugations (referred to in FIG. 11 ).

Such a treatment of the protective jacket 20 could also be of help forimproving the bond or constrain among the insulating cover 18 and theprotective jacket 20.

As an alternative, the tube 12 and the cover 18 are obtained, with thecover 18 having no slit and with no cutter being arranged, and theprotective jacket 20 is applied around the cover 18 before the same isapplied to the tube 12. At this stage, the tube 12—covered by theanti-corrosion layer 16—is inserted into the longitudinal opening of thetubular cover 18 coated with tubular jacket 20. In this case, specificexpedients should be provided for ensuring a proper bonding of the tube12 and the cover 18.

In this case, as it will be understood, the thermal insulation isimproved owing to the fact that no slit is arranged and subsequentlyclosed.

However, a method as previously described (with a cover delimiting aslit for the inner tube insertion) makes it possible to obtain pipeslonger than the now recalled second alternative, since when an innertube 12 is inserted into an insulating cover 18 as in the latter case,the tube 12 is subjected to a stress higher than the case with the coverdelimiting a slit.

Moreover, the first method described for inserting the inner tube 12 inan insulating cover 18 ensures an improved adhesion among such layers.

In this way, it is possible to obtain the final pipe 10.

After the pipe 10 has been wholly obtained, i.e. all its layers and/orcoatings have been applied, some further steps can be present:

-   -   cooling the pipe 10 (as shown in FIG. 12 ) and/or the protective        jacket 20 and/or the insulating cover 18 and/or the        anti-corrosion layer 16, and/or    -   marking the pipe with any suitable marking, and/or    -   cutting the pipe 10 and/or the inner tube 12 and/or the        insulating cover 18 and/or the protective jacket 20 to a        predetermined length, for example of 10 ft up to 200 ft, and/or    -   winding the pipe 10 in a reel.

As can be understood, the present invention provides advantages overknown prior art.

It will be understood that various details of the present invention maybe changed without departing from the scope of the presentspecification. Furthermore, the foregoing description is for the purposeof illustration only, and not for the purpose of limitation.

The invention claimed is:
 1. A method for obtaining a pipe suitable forconveying fluids in HVACR applications, wherein said pipe comprises aninner tube delimiting an inner space or passageway for a fluid, aninsulating cover and an anti-corrosion layer, comprising the followingsteps: providing an inner tube, providing an insulating cover, providingan anti-corrosion material and applying the anti-corrosion material toat least one portion of an outer surface of the inner tube, obtaining ananti-corrosion layer from the anti-corrosion material, comprising a stepof inserting the inner tube, coated with the anti-corrosion layer,inside the insulating cover or comprising a step of applying theinsulating cover around the inner tube, coated with the anti-corrosionlayer, and comprising the steps of longitudinally cutting the insulatingcover, thereby defining a longitudinal slit therein and of inserting theinner tube in the slit of the insulating cover.
 2. The method accordingto claim 1, wherein the step of applying the anti-corrosion materialcomprises bonding, gluing, spraying, coating, applying, extruding, orheat welding the anti-corrosion material, in order to obtain theanti-corrosion layer.
 3. The method according to claim 1, wherein saidinserting step comprises feeding to a coating machine the inner tube,enlarging the slit by means of enhancing means and inserting the innertube inside the longitudinal slit, in order to insert all along theinner tube inside the insulating cover.
 4. The method according to claim1, comprising a step of closing the slit by welding by hot air or UVrays or gluing.
 5. The method according to claim 1, comprising the stepof extruding and/or vulcanizing and/or polymerizing the insulatingmaterial in order to obtain the insulating cover.
 6. The methodaccording to claim 1, comprising the following steps: providing aprotective material suitable to make a protective jacket, and/orextruding the protective material in order to obtain a protective jacketon and/or over and/or all around the insulating cover or before or afterthe step of inserting the inner tube inside the insulating cover orapplying the insulating cover around the inner tube, providing a tubularprotective jacket or a sheet made of protective material suitable formaking the protective jacket, and/or before or after the step ofinserting the inner tube inside the insulating cover or applying theinsulating cover around the inner tube, applying or obtaining a tubularjacket around the tubular insulating cover or coupling said sheet madeof protective material to a sheet of insulating cover and then foldingsuch coupled layers so as to obtain a tubular insulating cover with anouter tubular jacket.
 7. The method according to claim 1, comprising thefollowing steps: knurling said protective jacket, in order to obtain aknurled or waved or rough or with annular rings pattern for saidprotective jacket, and/or cooling the pipe and/or the insulating coverand/or the protective jacket and/or the anti-corrosion layer, and/orcutting the pipe to a predetermined length, and/or marking the pipe,and/or winding the pipe in a reel.